🔍 Key Concepts

• Sea ice concentration scales used in navigation and ice charts • Difference between terms like open pack, close pack, and very close pack • How many tenths of the sea surface are covered by ice vs. open water

💭 Think About

• Think about whether open pack should mean mostly ice or mostly open water. • Compare what you would intuitively call close pack ice versus open pack ice when looking from a ship’s bridge. • Arrange the options from "least ice" to "most ice" and decide where the transition from mostly open water to mostly ice might be.

✅ Before You Answer

• Verify which range would still allow large areas of open water between ice floes. • Check that close pack ice would logically have a higher concentration than open pack ice. • Confirm that very open pack (if it existed as a term) would imply even less ice than open pack.